A-Level ChemistryYear 2022Q14
13147 14 The standard enthalpy of combustion of ethane can be estimated using average bond enthalpies. (a) Define the following terms: (i) standard enthalpy of combustion [2] (ii) average bond enthalpy [2] (b) Suggest why the bond enthalpy value for O O is not an average value. [1] 13147 [Turn over (c) The complete combustion of ethane can be represented by the equation: 2C2H6 + 7O2 → 4CO2 + 6H2O Use the bond enthalpies in the table below to calculate the standard enthalpy of combustion for ethane. Bond Bond enthalpy /kJ mol-1 C H 413 C C 348 O O 497 C O 803 O H 464 [4] (d) Suggest why a mixture of ethane and oxygen is stable at room temperature and does not react to form carbon dioxide and water. [1]
Paper Source:GCE-Chemistry-467-Summer2022-AS 2%2C Further Physical and Inorganic Chemistry and an Introduction to Organic Chemistry-Paper.pdf
Get full Socratic AI guidance on this question — free in the Applaa desktop app
Appy Buddy guides you step-by-step toward the answer without giving it away. Type your attempt and get instant, mark-scheme-aware clues that teach you to think like an examiner.
Applaa Desktop App
Join Applaa Community
Create your own games, learn AI concepts, program interactive apps, and share with a kid-safe community approved by parents. Free forever on Windows and Mac.
Download Free
Available for Windows and macOS · COPPA Compliant
Exam Specification Info
This question is part of the UK A-Level Chemistry syllabus. In the actual exam, structured questions typically require linking specific keywords to gain full marks. Applaa helps you drill these topics.
Syllabus levelAdvanced Level (A-Level)
SubjectChemistry
Official MarksVariable (2–6 marks)